#### onenyala

##### New member

The method I use is as follows:

In the absence of an horizon I use a bucket of water and view the sun through both the index glass and the reflected sun in the bucket in the horizon glass. I bring both images of the sun together so they are superimposed on each other.

This gives me an observed altitude x 2.

Of course I take the exact time of the observation.

I use a DR obtained by GPS

I then proceed as follows:

Observed double Altitude corrected for index error / 2

Correct this altitude for refraction.

Height of eye is not applicable as the eye is on the plane of the ‘horizon’

Semi-diameter not applicable as the images of the sun are superimposed on each other.

From the true altitude the TZD is then known.

Using the data from the N.A for the GMT of the observation and the GPS position as a DR I then calculate the CZD.

Comparison then gives me the intercept and I calculate the bearing.

As the house is fixed there I use the same DR for all of the observations.

After having taken numerous observations (50 – 60) over the course of the summer I get a position which is about 3 miles south of the GPS position??

Has anybody any explanation?

Stuart Jones